Subset: combine Element and Attribut

I've created a combobox based on one Element (SalesOffice) and chosen a subset where I'm using a picklist where I did select certain Elements.
Now I would like to show in the combobox as selection parameters the Element (KC1, KC2,...) AND the responding Attribut (Name):
I couldn't find the right settings in the subseteditor. I can only choose between the element or the attribut.
Since I'm not so familiar with the Palo.SUbset() formula, I can also not make manual change in there:
=PALO.SUBSET("localhost_ETL/Controlling";"SalesOffice";1;"Name";;;PALO.PICKLIST({"All SalesOffice"."KC 1"."KC 2"."KC 3"."KC 4"."KC 5"};3);;;PALO.SORT(1;0;;0;;0;0))